KOLKATA, India -- The chief minister of India's West Bengal state, where a bird flu outbreak reportedly is spreading, Friday called the disease situation "very serious."

The description by Buddhadeb Bhattacharjee came as more areas in the eastern state reported chickens dying, the Press Trust of India said. The new areas included Burdwan and Bankura districts.

There were reports of crows and owls dying in Kolkata but the chief minister said they were no cause for alarm, PTI said.

But in the avian flu-affected areas, which cover four districts, Bhattacharjee was quoted as saying, "We will have to kill (400,000) birds in the affected districts," where he said the situation is "very serious."

He said the culling process would be completed in a week.

In some villages, government officials said residents had been demanding cash instead of official compensation certificates for participating in the culling.